A light bar secured onto a roof of an emergency or municipal vehicle provides a highly visible platform on which lighting devices are bolted, usually at discrete mounting points, and electrically signaled so as to produce warning light patterns for other vehicles and bystanders. Light bars are also used to carry lights that illuminate areas around the vehicle perimeter to improve lighting conditions for a first responder or other workers.
In operation, light bar lighting devices frequently feature flashing or rotating lighting components known to generate electromagnetic noise that interferes with other electronics and lighting signals. To mitigate the interference noise, previous lighting devices have received electrical power and control signals via dedicated wired connections. The wires, when routed through an internal compartment of a light bar, lessen effects of electromagnetic noise on the operation of sensitive telecommunications equipment inside the vehicle. But as the number of lights in a light bar increases, so does the number of wires routed from lighting equipment to a vehicle's master controller unit and junction box, which may be located in the trunk, in the engine compartment, under a seat within the passenger interior area of the vehicle, or on an interior surface of the roof.
The previous hard-wired, discrete mounting point installation techniques are labor-intensive to install, have bolt patterns and wire connections that do not provide interoperability with lighting devices available from various manufacturers, and do not provide for user-configurable lighting arrangements. For example, replacing a lighting device of a previous light bar entails opening a transparent protective shell by unscrewing or unclipping its fasteners, disconnecting power and signal wires from the lighting device, unfastening the lighting device from the light bar, replacing it with a lighting device having a compatible bolt pattern and wire connectors (often having a proprietary connector type available from a specific vendor), testing the newly installed lighting device, refastening the transparent protective shell, and repeating the process to the extent changes are necessary. Furthermore, due to the use of tools involved during this process, lighting configuration changes typically entail temporarily taking a vehicle out of service.